Summaryobjectives Artemisinin-derivative drugs are widely used to treat Plasmodium falciparum malaria and very few studies have investigated the quality of these medicines in Africa. We analysed the active ingredient contents of artemisinin-derivative drugs marketed in Kenya and DR Congo.methods We analysed tablets, capsules, dry suspensions and injections (IM) containing either artemether (AM), arteether (AE), artesunate (ARS) or dihydroartemisinin (DHA). The content of active ingredients and preservatives was determined quantitatively using validated HPLC-UV methods. All analyses were done according to European pharmacopoeia requirements.results Labelled active ingredients were identified in all samples, however with varying dosages. Nine of the 24 drug samples analysed did not comply with the pharmacopoeial requirements of 95-105%: seven samples were underdosed and two were slightly overdosed. DHA was the active ingredient in 57% of the underdosed samples. AE injections had the lowest drug content (77%). Two-thirds of the dry powder suspensions were either substandard or fake. Tablets were up to 23% out of range. Unidentified peaks were observed on the chromatograms of AE IM injections and a DHA dry powder.conclusions Counterfeit or substandard artemisinin-derivative drugs are being sold in parts of Africa, presenting a potential route for resistance development in the future. Appropriate measures need to be taken to maintain proper and safe use of these medicines.

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Owing to the development of parasite resistance to standard antimalarial treatments like chloroquine and sulfadoxine-pyrimethamine, the demand for Artemisia annua, a key ingredient for new and highly effective antimalarial drugs, is huge. Therefore selective and precise methods to determine the content of artemisinin in dry plant material and in raw impure extracts are needed. In this work a method is described for the clear separation and extraction of artemisinin from other plant components in the Artemisia annua L. plant by thin-layer chromatography (TLC). To obtain optimal extraction and recovery efficiency, several parameters were evaluted, including choice of extraction solvent, TLC plate type and sensitivity between UV and visible light. Method validation was performed on both the dry plant material and non-purified plant extracts. Toluene presented the highest extraction efficiency compared with petroleum ether, hexane and methanol. Reversed-phase plates showed more concentrated spots than normal-phase plates, while the sensitivity of the analysis in UV was comparable to that in visible light but less precise. The impure plant extracts were analyzed by both TLC and HPLC-UV at 215 nm and both methods met the requirements for linearity, selectivity, precision and accuracy. Hence, the proposed TLC method can easily be used for both qualitative and quantitative control of the raw plant extract in areas where advanced methods are scarce.

Simple methods of analysis like UV-spectrophotometry can be used to check drug quality routinely. A substantial proportion of the antimalarial drugs sold on the Congo DR market is of poor quality. Some batches contain little or no drug. This is a serious threat to public health in the region of Congo DR.

Background: Artemisinin-derivative formulations are now widely used to treat falciparum malaria. However, the dry powder suspensions developed for children are few and/or are of poor quality. In addition to the active compound, the presence of a suitable preservative in these medicines is essential. In this study, an evaluation of the preservative content and efficacy in some dry suspensions available on the Kenyan market was performed.